An IoT house alarm is just great. You get all the control and monitoring from a mobile device you always carry around.
I have chosen as a solution: iSmartAlarm ISA3G Home Security Alarm System
– has a build in node station with siren
– supports contact sensors: iSmartAlarm Accessories – Contact Sensor
– supports motion sensors: iSmartAlarm Accessories – Motion Sensor
– supports remote tags: iSmartAlarm RC3G Remote Tag for Home Security System
– supports IP security cameras: A full HD model iSmartAlarm ISC3 iCamera KEEP and a simpler spot camera iSmartAlarm Camera Spotlight, Pack of 1, ISC5
– supports additional satelite siren: iSmartAlarm Satellite Siren – 1 AS3G
– very important has full IFTTT support so can be linked to any event or device with IFTTT support. Interesting things like proximity lock can be implemented: when the smart phone leaves the house automatically arm the alarm. Complex additional alerts like flashing some IFTTT controlled lights at the same time with the siren, or social media alerts (automatic twitter, mail, sms or Facebook notifications)
I found it to be very reliable, very easy to control and fun to use. Has a very loud siren and the iCamera KEEP has HD resolution and can be controlled remotely through the smart phone. The camera is a PTZ camera with a 180 degree rotation range that can be controlled directly from the smart phone.
In case the alarm is triggered the camera automatically uploads video to the cloud as evidence.